From patchwork Tue Jan 15 18:12:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Davidlohr Bueso X-Patchwork-Id: 10764929 X-Patchwork-Delegate: jgg@ziepe.ca Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B8E1014E5 for ; Tue, 15 Jan 2019 18:13:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A7BDA2D467 for ; Tue, 15 Jan 2019 18:13:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9C5C92D4D8; Tue, 15 Jan 2019 18:13:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 42B702D467 for ; Tue, 15 Jan 2019 18:13:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731293AbfAOSNc (ORCPT ); Tue, 15 Jan 2019 13:13:32 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:44871 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731165AbfAOSNb (ORCPT ); Tue, 15 Jan 2019 13:13:31 -0500 Received: from localhost.localdomain (prv-ext-foundry1int.gns.novell.com [137.65.251.240]) by smtp2.provo.novell.com with ESMTP (TLS encrypted); Tue, 15 Jan 2019 11:13:26 -0700 From: Davidlohr Bueso To: akpm@linux-foundation.org Cc: dledford@redhat.com, jgg@mellanox.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, dave@stgolabs.net, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, Davidlohr Bueso Subject: [PATCH 4/6] drivers/IB,hfi1: do not se mmap_sem Date: Tue, 15 Jan 2019 10:12:58 -0800 Message-Id: <20190115181300.27547-5-dave@stgolabs.net> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20190115181300.27547-1-dave@stgolabs.net> References: <20190115181300.27547-1-dave@stgolabs.net> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This driver already uses gup_fast() and thus we can just drop the mmap_sem protection around the pinned_vm counter. Note that the window between when hfi1_can_pin_pages() is called and the actual counter is incremented remains the same as mmap_sem was _only_ used for when ->pinned_vm was touched. Cc: mike.marciniszyn@intel.com Cc: dennis.dalessandro@intel.com Signed-off-by: Davidlohr Bueso Reviewed-by: Ira Weiny --- drivers/infiniband/hw/hfi1/user_pages.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c index df86a596d746..f0c6f219f575 100644 --- a/drivers/infiniband/hw/hfi1/user_pages.c +++ b/drivers/infiniband/hw/hfi1/user_pages.c @@ -91,9 +91,7 @@ bool hfi1_can_pin_pages(struct hfi1_devdata *dd, struct mm_struct *mm, /* Convert to number of pages */ size = DIV_ROUND_UP(size, PAGE_SIZE); - down_read(&mm->mmap_sem); pinned = atomic_long_read(&mm->pinned_vm); - up_read(&mm->mmap_sem); /* First, check the absolute limit against all pinned pages. */ if (pinned + npages >= ulimit && !can_lock) @@ -111,9 +109,7 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np if (ret < 0) return ret; - down_write(&mm->mmap_sem); atomic_long_add(ret, &mm->pinned_vm); - up_write(&mm->mmap_sem); return ret; } @@ -130,8 +126,6 @@ void hfi1_release_user_pages(struct mm_struct *mm, struct page **p, } if (mm) { /* during close after signal, mm can be NULL */ - down_write(&mm->mmap_sem); atomic_long_sub(npages, &mm->pinned_vm); - up_write(&mm->mmap_sem); } }